Electrical connection



Sept. 5, 1933.

T. P. SEARL ES ELECTRICAL CONNECTION Filed Dec. '5, 1931 INVENTOR T/zeodore P Sear/es ATTORNEY Patented Sept. 5, 1933 UNITED STATES PATENT OFFICE ELECTRICAL CONNECTION Application December 5, 1931.. Serial No. 579,276

8 Claims.

This invention relates to electrical connections and more particularly to a so-called solderless connection or tap for main and branch conductors so constructed that when clamped on said conductors the part or parts actually forming the electrical connection will be insulated from outside contact thus rendering unnecessary the application of additional insulation, as by means of insulating tape. The taping of taps, which is avoided by use of the present invention, is a source of considerable expense in a job of substantial size.

An important object of the invention is to provide an improved tap or connection. Another important feature relates to the means for insulating the internal conducting members of the connection from external contact.

According to a preferred form of the invention, the tap is arranged to hold the end of a branch conductor parallel to a main conductor and comprises two metal clamp plates having at one position opposite grooves to receive and grip an exposed portion of the conducting core of an insulated main conductor and at another position with opposed grooves to receive and grip an exposed portion of an insulated branch conductor. The clamping plates are preferably drawn together to efiect a clamping action by means acting between the two sets of grooves. For insulating purposes, the clamping plates or members are embedded in bodies of insulating material which leave only the adjacent sides of the clamping members exposed. The clamping members and the individual or half shells of insulating material are clamped on the conductors by securing devices, such as screws or bolts passing therethrough between the sets of grooves, each screw passing through and having its head in engagement with a plate at the outer side of one of the half shells and being screwed into the other plate.

In order to prevent electrical connection between the clamping members and the screws,-the latter are smaller in diameter than the corresponding holes in the metal clamp members and are insulated therefrom as by means of tubes of insulating material surrounding said screws where they pass through the corresponding, openings in the clamp members.

Other objects and advantages will appear upon consideration of the folldwing description and of the accompanying drawing in which Fig. 1 is a view showing the preferred form of tap connecting a main conductor and a branch conductor;

Fig. 2 is a view similar to Fig. 1, one half of the tap being removed and certain parts being shown in section;

Fig. 3 is a section taken along the line 3-3 of Fig. 1; and

Fig. 4 is a section taken along the line 4-4 of Fig. 1.

Referring to the drawing, 10 designates a main conductor having a conducting core 11 and an insulating covering 12 of suitable material which may be built up in layers; and 13 designates a branch conductor having a core 14 and a covering 15 of suitable insulation. These conductors are shown as connected by a tap 16, embodying the present invention, clamped on the uncovered core at the end of the branch conductor and on a suitably located uncovered portion of the core of the main conductor 10. r

The tap 16 is made up of two parts which are similar in most respects. The electrical connection between the conducting cores 11 and 14 is effected by means of clamp members or plates 17, one for each of said two parts and each of these clamp members is provided with a groove 18 to receive one side of the core 11 of the main conductor and a groove 19 to receive one side of the core 14 of the branch conductor.

These clamp members or plates 17 are rounded at their ends and sides (Figs. 3 and 4) and each is embedded in or enclosed except at its side by 5 a body 20 of insulating material which constitutes substantially half of an insulating covering or shell by which outside contact with the clamp members 17 is prevented. As indicated in Fig.

2. each insulating covering 20 for one of the clamp members 17 has a suitably shaped opening at the end of each groove, and these openings are preferably somewhat larger than the ends of the corresponding grooves so as to receive reduced portions of the insulating coverings of the conductors which protect the ends of said grooves. Also with this arrangement the outer part of the insulation in each instance, covers the corresponding openings in the insulating bodies or covers 20.

According to the preferred form of the invention the two clamp members 12 and the two shells or covers 20, which may be moulded thereon, are clamped on the cores of the insulated conductors 10 and 13 by suitable means'such as bolts or screws 21 passing through the clamp members 1'? between the grooves 18 and 19 and cooperating with metal members or plates at the outer surface of the covers 20 and embedded in the material thereof. As illustrated the plates 22 are provided withinclined sides and ends so as to be larger at the inner surface and to enable the insulating material to be moulded over the pro jecting parts and hold the plates 22 firmly in place. In order to avoid bringing the insulating material to too thin an edge at the sides of the plates, the sides are provided with offsets 23 which practically determine the thickness of the insulating material at the'corresponding edges.

The screws 21 are provided with suitable heads 24 which are positioned in suitable countersunk openings in one of the plates 22 and at their other ends are screwed into internally threaded openings in the other plate 22. This arrangement enables the halves of the tap to be gripped firmly on the conductors. It is necessary, however, to insulate the screws 21 from. the clamp members 17, and preferably this is done by providing holes or openings in the clamp members of greater cross section than the shanks of the screws and placing in these holes tubes 25 of insulating material through which the shanks of the screws are passed. For convenience the holes in the insulating covers are'made of the same diameter as' the holes in the clamp members and the tubes 25 are accordingly made of greater length. Preferably the heads of the screws 21 are nearly flush with the outer face of the corresponding plate 22 and the turning of the threaded end of the screw in the corresponding plate or compound nut 23 is effected by a suitable wrench inserted into a socket 26 which may be hexagonal in cross-section.

Although the insulating material of the parts or covers 20 may be of any suitable material, bakelite is preferably used, and each half of the tap may be formed by setting the metal plates in a suitable die and forcing in molten bakelite under suitable pressure and temperature, preferably a pressure of 3000 pounds and at a temperature of 300 F. The metal plates and bakelite in each half of the tap form unitary structures, the adherence of the bakelite to the metal plates being increased in any suitable or well-known manner as by roughening the metallic plates or providing them with a plurality of small holes into is completed the two metal clamp plates embrace the uninsulated portion of the main conductor or cable at one side of the tap and the uninsulated end of the branch cable at the other side, thus making a substantially perfect electrical connection which is completely insulated for all practical purpose. There are, however, seams between the halves of the tap and under very exacting conditions it may be necessary to seal these seams as by use of a suitable cement.

The foregoing detailed description has been given for clearness of understanding and no undue limitation should be deduced therefrom, but the appended claims should be construed as broadly as possible in view of the prior art.

Having thus described my invention, I claim:

1. A tap to connect parallel portions of two conductors, comprising two clamp members having aligned openings therethrough and each having two grooves to receive portions of the conductors; means for insulating the clamp members from outside contact including tubes of insulation in said openings and half shells of insulating ma terial enclosing and fitting over said clamp mom bers except at their inner faces, and means for drawing theparts of the tap together on the conductors including fastening devices passing through the half shells and clamp members between the grooves in the latter and acting on the half shells to force the clamp members together. 2. A tap to connect a branch conductor with a main conductor, comprising two metal clamp members having at their adjacent faces two pairs of opposed grooves in parallel arrangement to receive said branch conductor and said main conductor respectively, bodies of insulating material in which said metal clamp members are embedded except at their inner faces, said bodies of insulating material and said metal clamp members-having one or more openings therethrough between the grooves, a tube of insulating material in each opening in each clamp member and the corresponding opening in the associated body of insulating material, and means acting upon said bodies of insulating material'for clamping the two metal clamping members together to grip the conductors, including a fastening member passing through acorresponding tube and the opposed clamping members and associated bodies of insulating material.

3. A tap to connect a branch conductor with a main conductor, comprising two metal clamp members having at their adjacent faces two pairs of opposed grooves in parallel arrangement to receive said branch conductor and said main conductor respectively, bodies of insulating material enclosing said metal clamp members except at their inner faces, said bodies of insulating material and said metal clamp members having one or more openings therethrough between the grooves, a plate embedded in one of said bodies at its outer face and having a threaded opening in alignment with each of said openings in the corresponding body and clamp member and of smaller cross section, a tube of insulating material in each opening in each clamp member and the correspondingopening in the associated body of insulating material, and means for clamping the metal clamping members, the associated bodies of insulating material and the plate together including a fastening member passing through at least one tube in the opposed clamping members and associated bodies of insulating material and threaded into said plate.

4. .A tap to connect a branch conductor with a main conductor, comprising two metal clamp members having at their adjacent faces two pairs of opposed grooves in parallel arrangement to receive said branch conductor and said main conductor respectively, bodies of insulating material enclosing said metal clamp members except at their inner faces, said bodies of insulating material and said metal clamp members having one or more openings therethrough between the grooves, a plate embedded in each of said bodies at its outer face and having an opening therethrough in alignment with each opening in the corresponding body and clamp members, each opening in one of said plates being internally threaded and of smaller diameter than the corresponding openings in the clamping members and bodies, a tube of insulating material in each opening in each clamp member and the corresponding opening in the associated body of insulating material, and means for clamping the metal members and the associated bodies of insulating material and the plates together including a fastening member passing through at least its one of the corresponding tubes in the opposed clamping members and associated bodies of insulating material and into said plate having threaded openings.

5. A tap to connect a branch conductor with a main conductor, comprising two metal clamp members having at their adjacent faces two pairs of opposed grooves in parallel arrangement to receive said branch conductor and said main conductor respectively, bodies of insulating material enclosing said metal clamp members except at their inner faces, said bodies of insulating material and said metal clamp members having at least one opening therethrough between the grooves, a tube of insulating material in each opening in each clamp member, and means for clamping the metal clamping members and the associated bodies of insulating material together including a fastening member with a screw threaded end passing through at least one corresponding tube in the opposed clamping members and associated bodies of insulating material, and a nut at the outer side of one of said bodies into which the threaded end of said fastening member is screwed.

6. A tap to connect parallel portions of two conductors having insulation thereon, comprising two parts each including a clamp member having two grooves to receive portions of the conductors from which the insulation has been removed, a shell of insulating material secured to such clamp member and enclosing the same except at its grooved face, and a plate secured in each shell atthe outer side thereof, the clamp member having openings therethrough, and the shells and the plates having openings in alignment with those in the clamp members and the plates having openings'in alignment with those in the shells and in the clamp members but of smaller diameter than those in the clamp members, and the openings in 7. A tap to connect parallel portions of two conductors, comprising two clamp members each having two grooves to receive portions of the conductors and having aligned openings therethrough; means for insulating the clamp members from outside contact including tubes of insulation in said openings and half shells of insulating material enclosing said clamp members except at their inner faces; and means for drawing the parts of the tap together on the conductors including fastening devices passing through the half shells and clamp members and acting on the half shells to force the clamp members together.

8. A tap to connect parallel portions of two conductors, comprising two clamp members each having two grooves to receive portions of the conductors and having aligned openings therethrough; means for insulating the clamp members from outside contact including half shells of insulating material enclosing said clamp members except at their inner faces and having openings therethrough corresponding to the openings in said clamp members: and means for drawing the parts of the tap together on the conductors including one or more fastening devices acting on the half shells to force the clamp members together, each fastening device having a metal portion passing through openings in the half shells and through openings in the clamp members with substantial clearance.

THEODORE P. SEAR/LES. 

